CD52 and relapsing-remitting multiple sclerosis: Alemtuzumab is an anti-CD52 monoclonal antibody approved for the treatment of relapsing-remitting multiple sclerosis (RRMS), that has been shown in clinical trials to reduce clinical relapses, disability progression, magnetic resonance imaging (MRI) lesion activity and brain volume loss, with a well-known safety and tolerability profile [8–13].